26768482 Speed Control of Dc Motor Pwm

8/9/2019 26768482 Speed Control of Dc Motor Pwm

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A Project Report Submitted to the

ELECTRICAL ENGINEERING

DEPARTMENT

AS TERM WORK FOR THE SUBJECT

PROJECT

OF SEMESTER VIII

OF

BE (Electrical)

GUIDED BY: PREPARED BY:

Lect. HITARTH BUCH

Mr. RAHUL PARMARMr. SUSHIL RATHOD

Mr. HARSHAD PATELMr. CHETAN KOTHIYAMr. VIKRAMSINH MALIVAD

ELECTRICAL ENGINEERING DEPARTMENT

L. E. COLLEGE, MORBI-2

SAURASHTRA UNIVERSITY, RAJKOT

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YEAR 2007.

LUKHDHIRJI ENGINEERINGCOLLEGE

MORBI -363642

CERTIFICATEThis is to certify that the project work

titled SPEED CONTROL OF DC

MOTOR USING PWM TECHNIQUE

is being submitted by

NAME ROLL NO. EXAM. NO.

Mr. RAHUL PARMAR 30Mr. SUSHIL RATHOD 46Mr. HARSHAD PATEL 33Mr. CHETAN KOTHIYA 22Mr. VIKRAMSINH MALIVAD 24

for fulfillment of partial requirements ofSemester VIII of the degree Bachelor of

Engineering (Electrical) of

Saurashtra University for the academic

year 2007.

GUIDED BY: HEAD OF THE DEPARTMENT

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LECT. HITARTH BUCH


DEPARTMENTL. E. COLLEGE

PROF. S. P. SAPRE


DEPARTMENTL. E. COLLEGE

Place: MORBI Date:

ACKNOWLEDGEMENT

We express our deep and sincere thanks to our guide Mr. Hitarth Buch,

Lecturer in Electrical Engineering Department, L. E. College, Morbi. Initially he

helped us in selecting this project and then guided us throughout the project. He

also helped us by taking a lot of pain and sacrificing his personal valuable time

in completion of this practical project as well as the project report.

Next, we would like to express our deep gratitude towards Mr. K. B.

Rathod, Asst. Prof. in Electrical Engineering Department and Prof. S. P. Sapre,

Head of Electrical Engineering Department, who motivated us at one or anotherstage of the project work.

We express our gratitude to the staff members of Electrical Engineering

Department, who directly or indirectly helped us.

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Mr. RAHUL PARMARMr. SUSHIL RATHOD

Mr. HARSHAD PATELMr. CHETAN KOTHIYAMr. VIKRAMSINH

MALIVAD

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ABSTRACT

The aim of development of this project is towards providing

efficient and simple method for control speed of DC motor using pulse width

modulation technique. The modulation of pulse width is obtained using dual

timer IC - NE556.

There are several methods for controlling the speed of DC motors.

One simple method is to add series resistance using a rheostat. As considerable

power is consumed in the rheostat, this method is not economical. Another

method is to use a series switch that can be closed or opened rapidly. This type

of control is termed as chopper control. The PWM based chopper circuit

smoothly controls the speed of general purpose DC motors.

To get desired modulation of pulse width as output, we have

fabricated astable multivibrator and monostable multivibrator circuit using single

dual timer IC NE 556. The width of the pulse is changed by varying the control

voltage of the monostable circuit.

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TABLE OF CONTENTS

ACKNOWLEDGEMENT .................................................................. iii

ABSTRACT v

TABLE OF CONTENTS ................................................................... vi

LIST OF TABLES ......................................................................... viii

GLOSSARY OF TERMS .................................................................. ix

0.1 GOAL ................................................................................. 110.2 Pulse Width Modulation (PWM) Basics ................................ 112.1 GOAL ................................................................................. 173.1 GOAL ............................................................................... 243.2 DESIGN OF ASTABLE MULTIVIBRATOR ...............................244.1 GOAL ................................................................................. 26

4.3 PULSE WIDTH MODULATION TECHNIQUE: ............................... 27

5.1 GOAL ................................................................................. 305.2 TESTING PROCEDURE AND CALIBRATION ..........................305.2.1 TESTING OF PULSE-WIDTH MODULATION CIRCUIT .......306.1 GOAL ............................................................................... 326.2 WAVE-FORM OBSERVATION ............................................. 327.1 GOAL ................................................................................. 34

7.2 COMPONENT LIST .......................................................... 348.1 GOAL ............................................................................... 368.2 TIME ANALYSIS ................................................................ 368.3 COST ANALYSIS ............................................................... 379.1 GOAL ................................................................................ 399.2 CONCLUSION .................................................................... 3910.1 GOAL ............................................................................... 4110.2 POSSIBLE MODIFICATIONS .............................................. 41

APPENDIX 42

DATASHEETS ........................................................................... 42

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BIBLIOGRAPHY ........................................................................... 45

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LIST OF TABLES

TABLE 6-1 WAVE-FORM OBSERVATION

TABLE 6-2 VOLTAGE SPEED CHARACTERISTICS

ON NO-LOAD

TABLE 7-1 PULSE-WIDTH MODULATION

TABLE 7-2 DRIVER CIRCUIT

TABLE 8-1 TIME ANALYSIS

TABLE 8-2 COST ANALYSIS

TABLE 10-1 FUTURE MODIFICATIONS

LIST OF FIGURES

FIG. 1.1 UNMODULATED, SINE MODULATED PULSES

FIG. 1.2 SPECTRA OF PWM

FIG. 1.3 SINE SAWTOOTH PWM

FIG. 1.4 TRAILING EDGE MODULATION

FIG. 1.5 REGULAR SAMPLED PWM

FIG. 1.6 SATURATED PULSE WIDTH MODULATION

FIG. 2.1 PIN DIAGRAM

FIG. 2.2 ASTABLE OPERATION

FIG. 2.3 MONOSTABLE OPERATION

FIG. 4.1 BLOCK DIAGRAM

FIG. 4.2 CIRCUIT DIAGRAM

FIG. 4.3 PWM SIGNAL OF VARYING DUTY-CYCLES

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GLOSSARY OF TERMS

AC - Alternating Current

NPT - Non Punch Through

CRO - Cathode Ray Oscilloscope

DC - Direct Current

IC - Integrated Circuit

PWM - Pulse Width Modulation

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1.

INTRODUCTION

TO PWM TECHNIQUE

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0.1 GOAL

To explain PULSE WIDTH MODULATION technique in brief.

0.2 Pulse Width Modulation (PWM) Basics

There are many forms of modulation used for communicating

information. When a high frequency signal has amplitude varied in response to alower frequency signal we have AM (amplitude modulation). When the signalfrequency is varied in response to the modulating signal we have FM (frequencymodulation. These signals are used for radio modulation because the highfrequency carrier signal is needs for efficient radiation of the signal. When

communication by pulses was introduced, the amplitude, frequency and pulsewidth become possible modulation options. In many power electronic converterswhere the output voltage can be one of two values the only option is modulation ofaverage conduction time.

Fig. 1.1 Unmodulated, sine modulated pulses

1. Linear Modulation

The simplest modulation to interpret is where the average ON timeof the pulses varies proportionally with the modulating signal. The advantage oflinear processing for this application lies in the ease of de-modulation. Themodulating signal can be recovered from the PWM by low pass filtering. For asingle low frequency sine wave as modulating signal modulating the width of afixed frequency (fs) pulse train the spectra is as shown in Fig 1.2. Clearly a lowpass filter can extract the modulating component fm.

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Fig. 1.2 Spectra of PWM

2. Sawtooth PWM

The simplest analog form of generating fixed frequency PWM is bycomparison with a linear slope waveform such as a saw tooth. As seen in Fig 1.2the output signal goes high when the sine wave is higher than the saw tooth. Thisis implemented using a comparitor whose output voltage goes to logic HIGH whenne input is greater than the other. Other signals with straight edges can be usedfor modulation a rising ramp carrier will generate PWM with Trailing EdgeModulation.

Fig. 1.3 Sine Sawtooth PWM

It is easier to have an integrator with a reset to generate the ramp inFig1.4 but the modulation is inferior to double edge modulation.

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Fig. 1.4

Trailing

Edge

Modulation

3. Regular Sampled PWM

The scheme illustrated above generates a switching edge at the

instant of crossing of the sine wave and the triangle. This is an easy scheme toimplement using analog electronics but suffers the imprecision and drift of allanalog computation as well as having difficulties of generating multiple edgeswhen the signal has even a small added noise. Many modulators are nowimplemented digitally but there is difficulty is computing the precise intercept of themodulating wave and the carrier. Regular sampled PWM makes the width of thepulse proportional to the value of the modulating signal at the beginning of thecarrier period. In Fig 1.5 the intercept of the sample values with the triangledetermine the edges of the Pulses. For a saw tooth wave of frequency fs thesamples are at 2fs.

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Fig. 1.5 Regular Sampled PWM

There are many ways to generate a Pulse Width Modulated signalother than fixed frequency sine sawtooth. For three phase systems the modulationof a Voltage Source Inverter can generate a PWM signal for each phase leg bycomparison of the desired output voltage waveform for each phase with the samesawtooth. One alternative which is easier to implement in a computer and gives alarger modulation depth is using space vector modulation.4. Modulation Depth

Fig. 1.6

Saturated

Pulse Width

Modulation

For a single phase inverter modulated by a sine-sawtoothcomparison, if we compare a sine wave of magnitude from -2 to +2 with a trianglefrom -1 to +1 the linear relation between the input signal and the average outputsignal will be lost. Once the sine wave reaches the peak of the transgle the pulseswill be of maximum width and the modulation will then saturate. The Modulationdepth is the ratio of the current signal to the case when saturation is just starting.Thus sine wave of peak 1.2 compared with a triangle with peak 2.0 will have amodulation depth of m=0.6.

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THEORY

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2.1 GOAL

To study about Dual timer IC NE556 and its operation as Asteble

and Monostable Multivibrator.

2.2 INTRODUCTION

A popular version is the NE555 and this is suitable in most caseswhere a 555 timer is specified. The 556 is a dual version of the 555 housed in a14-pin package, the two timers (A and B) share the same power supply pins.The circuit diagrams show a 555, but they could all be adapted to use one halfof a 556.

The circuit symbol for a 556 is a box with the pins arranged to suitthe circuit diagram: for example 555 pin 8 at the top for the +Vs supply, 555 pin3 output on the right. Usually just the pin numbers are used and they are notlabeled with their function.

The 556 can be used with a supply voltage (Vs) in the range 4.5 to15V (18V absolute maximum).

2.3 PIN DESCRIPTION

Fig. 2.1 Pin Diagram

The IC 556 is a dual timer 14 pin IC as shown in fig above. Thereare two sets of six pins (pin no.1 6 and pin no. 8 - 13) are same as the pin no.2 7 in IC 555. The brief description of each pin is as follows.

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Pin 1 & 13: Discharge. This pin is connected internally to the collector oftransistor Q1. When the output is high Q1 is OFF and acts as an open circuit toexternal capacitor C connected across it. On the other hand, when the output is

low, Q1 is saturated and acts as a short circuit, shorting out the externalcapacitor C to ground.

Pin 2 & 12: Threshold. This is the non-inverting input of comparator 1,which monitors the voltage across the external capacitor. When the voltage atthis pin is greater than or equal to the threshold voltage 2/3 VCC, the output ofcomparator 1 goes high, which inturn switches the output of the timer low.

Pin 3 & 11: Control. An external voltage applied to this terminal changesthe threshold as well as trigger voltage. Thus by imposing a voltage on this pin

or by connecting apotbetween this pin and ground, the pulse width of theoutput waveform can be varied. When not used, the control pin should bebypassed to ground with a 0.01F Capacitor to prevent any noise problems.

Pin 4 & 10: Reset. The 555 timer can be reset (disabled) by applying anegative pulse to this pin. When the reset function is not in use, the resetterminal should be connected to +VCC to avoid any possibility of false triggering.

Pin 5 & 9: Output. There are two ways by which a load can beconnected to the output terminal: either between pin 3 and ground or between

pin3 and supply voltage +VCC. When the output is low the load current flowsthrough the load connected between pin3 and +VCC into the output terminal andis called sink current. The current through the grounded load is zero when theoutput is low. For this reason the load connected between pin 3 and +VCC iscalled the normally on loadand that connected between pin 3 and ground iscalled normally off-load. On the other hand, when the output is high the currentthrough the load connected between pin 3 and +VCC is zero. The output terminalsupplies current to the normally off load. This current is called source current.The maximum value of sink or source current is 200mA.

Pin 6 & 8: Trigger. The output of the timer depends on the amplitude of

the external trigger pulse applied to this pin. The output is low if the voltage atthis pin is greater than 2/3 VCC. When a negative going pulse of amplitudegreater than 1/3 VCC is applied to this pin, comparator 2 output goes low, whichin turn switches the output of the timer high. The output remains high as long asthe trigger terminal is held at a low voltage.

Pin 7: Ground. All voltages are measured with respect to this terminal.

Pin 14: +VCC. The supply voltage of +5V to + 18V is applied to this pinwith respect to ground.

2.4 INPUTS OF 556

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Trigger input: when < 1/3 Vs ('active low') this makes the output high(+Vs). It monitors the discharging of the timing capacitor in an astablecircuit. It has a high input impedance > 2M .

Threshold input: when > 2/3 Vs ('active high') this makes the output low(0V)*. It monitors the charging of the timing capacitor in astable andmonostable circuits. It has a high input impedance > 10M .

Reset input: when less than about 0.7V ('active low') this makes theoutput low (0V), overriding other inputs. When not required it should beconnected to +Vs. It has an input impedance of about 10k .

Control input: this can be used to adjust the threshold voltage which isset internally to be 2/3 Vs. Usually this function is not required and thecontrol input is connected to 0V with a 0.01F capacitor to eliminateelectrical noise. It can be left unconnected if noise is not a problem.

The discharge pin is not an input, but it is listed here for convenience. Itis connected to 0V when the timer output is low and is used to dischargethe timing capacitor in astable and monostable circuits.

2.5 OUTPUT OF 556

The output of a standard 556 can sink and source up to 200mA.This is more than most chips and it is sufficient to supply many outputtransducers directly, including LEDs (with a resistor in series), low currentlamps, piezo transducers, loudspeakers (with a capacitor in series), relay coils(with diode protection) and some motors (with diode protection). The outputvoltage does not quite reach 0V and +Vs, especially if a large current is flowing.

2.6 APPLICATION

Astable - producing a square wave Monostable - producing a single pulse when triggered

2.7 ASTABLE OPERATION

If we rearrange the circuit slightly so that both the trigger andthreshold inputs are controlled by the capacitor voltage, we can cause the 555 totrigger itself repeatedly. In this case, we need two resistors in the capacitor

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http://c/Documents%20and%20Settings/L.E.%20-%20749/Desktop/www.kpsec.freeuk.com/555timer.html#astable#astablehttp://c/Documents%20and%20Settings/L.E.%20-%20749/Desktop/www.kpsec.freeuk.com/555timer.html#monostable#monostablehttp://c/Documents%20and%20Settings/L.E.%20-%20749/Desktop/www.kpsec.freeuk.com/555timer.html#monostable#monostablehttp://c/Documents%20and%20Settings/L.E.%20-%20749/Desktop/www.kpsec.freeuk.com/555timer.html#astable#astable


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charging path so that one of them can also be in the capacitor discharge path.This gives us the circuit shown to the left.

Fig. 2.2 Astable Operation

In this mode, the initial pulse when power is first applied is a bit

longer than the others, having duration of T= CRR ba *)(1.1 + .

However, from then on, the capacitor alternately charges anddischarges between the two comparator threshold voltages. When charging, Cstarts at (1/3)Vcc and charges towards VCC. However, it is interrupted exactlyhalfway there, at (2/3)VCC. Therefore, the charging time,

CRRtba*)(693.0

1 +=

When the capacitor voltage reaches (2/3)VCC, the dischargetransistor is enabled (pin 7), and this point in the circuit becomes grounded.Capacitor C now discharges through Rb alone. Starting at (2/3)VCC, it discharges

towards ground, but again is interrupted halfway there, at (1/3)VCC. Thedischarge time,

CRtb*693.0

2 =

The total period of the pulse train is CRRtt ba *)2(693.021 +=+

The output frequency of this circuit is the inverse of the period,

CRRf

ba *)2(

45.1

+=

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Note that the duty cycle of the 555 timer circuit in astable modecannot reach 50%. On time must always be longer than off time, because Ramust have a resistance value greater than zero to prevent the dischargetransistor from directly shorting VCC to ground. Such an action would immediatelydestroy the 555 IC.

One interesting and very useful feature of the 555 timer in eithermode is that the timing interval for either charge or discharge is independent ofthe supply voltage, VCC. This is because the same VCC is used both as thecharging voltage and as the basis of the reference voltages for the twocomparators inside the 555. Thus, the timing equations above depend only onthe values for R and C in either operating mode.

In addition, since all three of the internal resistors used to make upthe reference voltage divider are manufactured next to each other on the samechip at the same time, they are as nearly identical as can be. Therefore,changes in temperature will also have very little effect on the timing intervals,provided the external components are temperature stable. A typical commercial555 timer will show a drift of 50 parts per million per Centigrade degree oftemperature change (50 ppm/C) and 0.01%/Volt change in VCC. This isnegligible in most practical applications.

2.8 MONOSTABLE OPERATIONThe 555 timer configured for monostable operation is shown in

figure.

Fig. 2.3 Monostable Operation

Monostable multivibrator often called a one shot multivibrator Inmonostable mode, the timing interval, t, is set by a single resistor and capacitor,

as shown to the right. Both the threshold input and the discharge transistor (pins

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6 & 7) are connected directly to the capacitor, while the trigger input is held at+VCC through a resistor. In the absence of any input, the output at pin 3 remainslow and the discharge transistor prevents capacitor C from charging.

When an input pulse arrives, it is capacitively coupled to pin 2, the

trigger input. The pulse can be either polarity; its falling edge will trigger the 555.At this point, the output rises to +VCC and the discharge transistor turn off.Capacitor C charges through R towards +VCC. During this interval, additionalpulses received at pin 2 will have no effect on circuit operation.

Time period, RCT 1.1=

The value of 1.1RC isn't exactly precise, of course, but the roundoff error amounts to about 0.126%, which is much closer than component

tolerances in practical circuits, and is very easy to use. The values of R and Cmust be given in Ohms and Farads, respectively, and the time will be inseconds. You can scale the values as needed and appropriate for yourapplication, provided you keep proper track of your powers of 10. For example, ifyou specify R in megohms and C in microfarads, t will still be in seconds. But ifyou specify R in kilohms and C in microfarads, t will be in milliseconds. It's notdifficult to keep track of this, but you must be sure to do it accurately in order tocorrectly calculate the component values you need for any given time interval.

The timing interval is completed when the capacitor voltagereaches the +(2/3)VCC upper threshold as monitored at pin 6. When thisthreshold voltage is reached, the output at pin 3 goes low again, the dischargecapacitor (pin 7) is turned on, and the capacitor rapidly discharges back toground once more. The circuit is now ready to be triggered once again.

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3.

CIRCUIT DESIGN

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3.1 GOAL

To design circuit this gives square pulse of modulated pulse width

as output.

3.2DESIGN OF ASTABLE MULTIVIBRATOR

We have choosen astable frequency as 549 Hz. We have also takenvalue of capacitor C=0.01F and R1=10R2.

Frequency of output pulse

CRR

f

*)2(

45.1

21 +

=

Putting the values off, R1 and C

00000001.0*)210(

45.1549

22 RR +=

== K2200000001.0*549*12

45.12R

Therefore,

.220

22*10

*10 21

=

=

=

K

K

RR

3.3 DESIGN OF MONOSTABLE MULTIVIBRATOR

We have taken timing component for monostable multivibrator is2.42ms. The time period for monostable multivibrator ,

T = 1.1*R1*C1

Putting the values of T and C1 in above equation

.220

00000001.0*1.1

00242.0

*1.1 11

=

=

=

K

C

TR

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4.

CIRCUIT DESCRIPTION

AND WORKING

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4.1 GOAL

To explain working of the PWM circuit.

4.2 BASIC BLOCK DIAGRAM

As shown in block diagram there are mainly three blocks: AstableMultivibrator, Monostable Multivibrator and Driving Circuit.

Fig. 4.1 Block Diagram

The Basic Blocks are explained below:

Astable Multivibrator : This block produce square pulses of samefrequency according to time constant RC. These pulses are fed to next block astriggering pulses.

Monostable Multivibrator : This block produces square pulses of variablefrequencies. The frequency of output pulse can be varied by changing the value ofresistor shown in figure. These pulses are fed to the driving circuit.

Driving Circuit : This block provides power required to drive the motor. Asthe frequency of output pulses of Monostable multivibrator changes, the averagevoltage supplied to motor changes. Hence, the speed of motor changes.

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4.3 PULSE WIDTHMODULATION TECHNIQUE:

Modulation means to vary something. Pulse Width modulationmeans to vary the width of pulses to obtain desired output voltage.

As shown in the diagram above we have used IC556 for thegeneration of pulses. The left part of IC is used as astable mode to generatesquare pulses of frequency 549Hz and right part of IC is used as monostablemode. The output of astable mode is fed to the trigger pin (Pin no. 8) of themonostable circuit. This monostable circuit generates pulses of variable width.The Figure shows three different pulse-width modulation signals. Fig. shows apulse-width modulation output at a 10% duty-cycle i.e. the signal is ON for 10% of

period and 90% OFF. Figure also shows Pulse-width modulation output at 50 %and 90 % duty-cycle respectively

4.4 CIRCUIT DIAGRAM

Fig. 4.2 Circuit Diagram

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Fig. 4.3 PWM signal of varying duty-cycles

As shown in circuit diagram all the timing components are placed asper the calculation carried out in the portion Circuit Design.

A diode D1 is added in parallel with R5 to improve duty cycle in caseof Astable multivibrator. This D1 bypasses R2 during the discharging time of the

cycle so that TOFF depends only on R2 and C1 only. Hence, discharging timereduces and duty cycle improves.

Resistor R4 (22, 2W) serves as current limiter resistor. It avoidsoverheating of transistor T1 by limiting load current.

Transistor T1 drives the motor. T1 turns ON and OFF according tothe output pulses of monostable oscillator at pin no. 9. As the transistor getspulses on its base, it turns ON and motor runs.

A diode D2 acts as free wheeling diode. As the T1 turns ON andOFF with high frequency, energy is stored in winding of motor. During OFF periodthis energy is dissipated in form of circulating current through D2 and winding ofmotor. If free wheeling diode is not provided, it may damage the transistor T1.

The speed can be varied by adjusting VR1, which changes thethreshold value to which capacitor C1 in the monostable circuit is charged. This, inturn, determines its output pulse width and hence the average voltage applied tothe motor.

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The position of DPDT switch determines the direction of rotation ofmotor. By changing the position of switch, we can make the motor to rotate inforward or reverse direction.

For effective speed control, ON period of astable should be equal to

the maximum pulse width of monostable.

5.

TESTING AND

CALIBARATION

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5.1 GOAL

To give details about testing procedure.

5.2 TESTING PROCEDURE AND CALIBRATION

As in any technical project, it is necessary to test the work carriedout. Here also we carried out various tests on our project. We assembled thecircuit in section by section manner, tested the individual section and if requiredthe section component values were modified depending upon requirements. Theoverall testing and calibration was divided into following steps.

1) Testing of Pulse-width modulation Circuit

2) Testing of variation in speed with reference to change in DC voltage

5.2.1 TESTING OF PULSE-WIDTH MODULATION CIRCUIT

1) Connect the circuit connection.

2) Connect the power supply to the ICs from the linear regulator circuit

3) Observe the wave-form at PIN-9 of IC 556. Measure each output

voltage for each case in observation table shown in table 7.1

4) Vary the potentiometer and observe the effect on the load.

5.2.2 TESTING OF VARIATION IN MOTOR SPEED WITH REFERENCE TO

CHANGE IN VOLTAGE.

1) Keep supply voltage at its nominal value.

2) Observe the speed variation of motor and measure the DC voltage

by varying the potentiometer. Observe the speed variation and plot

the graphical representation.

3) Measure each output speed for each case and take observation in

observation table.

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6.

RESULTS

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6.1 GOAL

To give obtained results of the project.

6.2 WAVE-FORM OBSERVATION

TABLE 6-3 WAVE-FORM OBSERVATION

Sr.

No.

PIN NO TYPE OF WAVE-

FORM

INFERENCE

1. AT

PIN NO 9

OF IC 556

Square-wave of

voltage +12v

Operation of OP-

AMP in saturation

region alternatively

TABLE 6-4 VOLTAGE SPEED CHARACTERISTICS ON NO-LOAD

Sr. No. Output voltage Speed variation

1.

2.

3.

4.

5.

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7.

BILL OF MATERIAL

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7.1 GOAL

To give details of components used in project.

7.2 COMPONENT LIST

TABLE 7-1 PULSE-WIDTH MODULATION

Sr.

No.

Component

Type

Reference

Number

Value Remark

1 IC 556 IC 556 TIMER IC

2 RESISTOR R1 220K FIXED RESISTOR


4 RESISTOR R3 330 BISING RESISTOR

5 RESISTOR R4 22,2W CURRENT LIMITOR


7 VARIABLE

RESISTOR

VR1 10K VARIATION OF PULSE WIDTH

8 CAPACITOR C1 0.01F RC TIME CONSTANT9 CAPACITOR C2 0.01F RC TIME CONSTANT

TABLE 7-2 DRIVER CIRCUIT

Sr. No. Component Type Reference Number Remark

1 TRANSISTOR SL100 DRIVING TRANSISTOR

2 DIODE 1N4001 FREE WHEELING DIODE

3 DPDT SWITCH MOTOR DIRECTIONREVERSAL

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8.

TIME & COST ANALYSIS

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8.1 GOAL

To give time and cost analysis of the project

8.2 TIME ANALYSIS

TABLE 8-1 TIME ANALYSIS

SR.

NO.

TASK TIME

REQUIRED

(IN WEEKS)1 Selection of project 1

2 Study of fundamental theory 2

3 Design of overall circuitry and component selection and

purchasing components

1

4 Testing of individual sections (on GP Board) and making

necessary modifications

2

5 Integrated testing of the project (on GP Board) and

making necessary modifications

1

6 Assembling and testing of the project on final GP Board 17 Writing Project report 1

8 Computerization of the report ( including figures) 1

Total Time Required in Weeks 10

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8.3 COST ANALYSIS

TABLE 8-2 COST ANALYSIS

SR.

NO.

WORK / COMPONENT COST

Rs.

IC 556 30

RESISTORS 30

CAPACITORS 5

TRANSISTOR 15

GENERAL PURPOSE PRINTED CIRCUIT BOARD 20

PROJECT REPORT DATA ENTRY, PRINTING , XEROXING

AND BINDING CHARGES

600

TOTAL COST OF THE PROJECT 700

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9.

CONCLUSION

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9.1 GOAL

To conclude the work carried out.

9.2 CONCLUSION

From the project work, following points can be concluded.

1. It fulfils all the requirements for its application.

2. The motor responds to the average value of the pulses and not to the

individual pulses as the chopper works at high frequency.

3. Changing the duty-cycle of the pulse by changing the potentiometer changes

the average voltage level.

4. It is possible to improve overall performance of the chopper drive

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10.

FUTUREMODIFICATIONS

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10.1 GOAL

To highlight possible modifications that can be made in the project

for improving performance.

10.2 POSSIBLE MODIFICATIONS

Following are the possible future modifications in our project work.

TABLE 10-1 FUTURE MODIFICATIONS

Sr.

No.

Modification Purpose

1 Use of micro-

controller/micro-processor

for closed loop operation

Constant speed variation

2 Use of MOSFET or IGBT Higher voltage and power requirement

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APPENDIXDATASHEETS

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BIBLIOGRAPHY

1) Electronics For You EFY Enterprises Pvt. Ltd.

2) OPAMP and Linear Integrated Circuit R. A. Gayakwad.

3) Power Electronics Circuits, Devices and Applications - Rashid M. H.

4) Power Electronics - P. S. Bhimbara.

5) Texas Instruments Linear IC Data Book

6) WEB SITE SUPPORT - www.kpsec.freeuk.com

- www.datasheetcatelog.com
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